A slender, tufted perennial herb found in damp open ground by roads and lakes, on paths and in woodland and forest rides. 0-430 m (above Dent station, N.W. Yorks., and in the Caulderbeck Fells, Cumberland).
This species was first recorded from Angus in the 1790s, but did not begin to spread widely until the late 19th century. Claims for native status in Ireland are unproven. It has consolidated rather than extended its range since the 1962 Atlas.
Native of N. & S. America.
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Light (Ellenberg): 7
Moisture (Ellenberg): 7
Reaction (Ellenberg): 5
Nitrogen (Ellenberg): 4
Salt Tolerance (Ellenberg): 0
January Mean Temperature (Celsius): 3.6
July Mean Temperature (Celsius): 14.6
Annual Precipitation (mm): 1267
Height (cm): 40
Perennation - primary
Life Form - primary
Clonality - primary
Count of 10km squares in Great Britain: 1053
Count of 10km squares in Ireland: 145
Count of 10km squares in the Channel Isles: 3
Atlas Change Index: 0.83
Weighted Changed Factor: 18
Weighted Change Factor Confidence (90%)
Atlas text references
1986. Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols.
1965. Vergleichende Chorologie der zentraleuropäischen Flora. Volume 1. 2 vols.
1974. The reproduction of Juncus tenuis and its dispersal. Transactions of the Botanical Society of Edinburgh. 42:187-190.